President Trump on Wednesday followed through on threats to strip the security clearance of former CIA director John Brennan, igniting a firestorm of criticism that the president was recklessly attempting to distract from his own political problems and silence high-profile critics.

Press secretary Sarah Huckabee Sanders announced the decision at a White House briefing, reading a statement from Trump that accused Brennan of making “a series of unfounded and outrageous allegations — wild outbursts on the internet and television — about this Administration.”

Brennan, who led the CIA during most of President Barack Obama’s second term, has emerged as one of Trump’s fiercest critics, denouncing his performance at a summit with Russian President Vladi­mir Putin last month as “treasonous.” On Tuesday, Brennan lambasted Trump’s personal character after he derided former White House aide Omarosa Manigault Newman as a “dog.”

“Any benefits that senior officials might glean from consultations with Mr. Brennan are now outweighed by the risk posed by his erratic conduct and behavior,” Trump said in his statement. “Mr. Brennan has a history that calls into question his objectivity and credibility.”

Trump added that he is reviewing the security clearances of nine other former officials, including former FBI director James B. Comey, all of whom have criticized the president or been targeted by congressional Republicans seeking to discredit the Russia probe.

The move sent shock waves through Washington’s political class and the intelligence community, which has traditionally sought to avoid public partisanship but has been dragged into the debate as Trump has accused what he calls the “deep state” of seeking to undermine his presidency through leaks of sensitive material.

Former CIA director John Brennan is sworn in before testifying at a hearing of the House Permanent Select Committee on Intelligence on May 23, 2017. (SAUL LOEB/AFP/Getty Images)

The president also has lashed out repeatedly against the ongoing investigation led by special counsel Robert S. Mueller III into possible contacts between the Trump campaign and Russian operatives accused of tampering in the 2016 presidential election.

Trump appeared to make a direct link in an interview with the Wall Street Journal on Wednesday. “I call it the rigged witch hunt,” Trump said of the Russia probe. “And these people led it. So I think it’s something that had to be done.”

Brennan was a longtime intelligence official who briefed three presidents and served as CIA station chief in Saudi Arabia, CIA chief of staff, director of the Terrorist Threat Integration Center, director of the National Counterterrorism Center, and assistant to the president for homeland security and counterterrorism.

His former colleagues rallied to his defense, hailing his service to the nation, including a key role in the 2011 operation that killed Osama bin Laden.

In a tweet Wednesday, former vice president Joe Biden said Trump’s decision was “unbecoming of a President” and praised Brennan as someone who “has never been afraid to speak up.”

“If you think it will silence John, then you just don’t know the man,” he wrote.

Brennan reacted to the news by comparing Trump’s actions to those of “foreign despots and autocrats.”

“I never, ever thought I’d see it here in the United States,” Brennan said on MSNBC. “I believe all Americans need to take stock of what is happening right now in our government — how abnormal and how irresponsible and how dangerous these actions are. If Mr. Trump believes this is going to lead me to just go away and be quiet, he is very badly mistaken.”

Sanders cast Trump’s decision as the outcome of an ongoing review of former and current officials whose conduct has led the president to question their willingness to “protect classified information.”

But since aides first raised the specter of Trump’s stripping Brennan and several others of their clearances, security experts have described such a move as unprecedented and warned that words and actions protected by the First Amendment are not grounds to take a clearance away.

“As far as we know, this is the first time that a president of the United States has individually taken action against somebody’s security clearance,” said Mark Zaid, an attorney who represents government employees in security-clearance disputes.

Last month, the White House said that along with Brennan and Comey, the president was scrutinizing former CIA director Michael V. Hayden, former national security adviser Susan E. Rice, former director of national intelligence James R. Clapper Jr. and former FBI deputy director Andrew McCabe.

On Wednesday, Sanders expanded that list to include former acting attorney general Sally Q. Yates, former FBI lawyer Lisa Page, former FBI agent Peter Strzok and Justice Department official Bruce Ohr, who was recently demoted.

Yates was fired by Trump last year after she defied the president and ordered federal attorneys not to defend his controversial travel ban. Strzok and Page, two of Trump’s favorite targets on Twitter, became the centerpiece of Republicans’ efforts to discredit Mueller’s Russia probe after anti-Trump texts between the two were revealed last year. Strzok was fired over the texts this week.

Ohr is also a frequent object of GOP criticism; he was named by Republicans in a memo earlier this year that targeted his ties to the former British intelligence officer who wrote the controversial dossier on the Trump campaign’s alleged contacts with Russian officials.

Comey lashed out at Trump, saying in a statement that the significance of his actions should not be lost in the constantly churning news cycle: “In a democracy, security clearances should not be used as pawns in a petty political game to distract voters from even bigger problems. This president befriends and praises despots and dictators like Putin and Kim Jong-un. Those friends provide stark contrast to patriotic Americans he disrespects, threatens, and calls enemies: a war hero like John McCain, members of our country’s free press, and devoted public servants like John Brennan.”

The timing of the announcement suggested that the president may also have been trying to distract public attention from saturation media coverage of accusations in Manigault Newman’s new book that Trump made racist statements before he took office that were captured on tape.

After Sanders’s briefing Wednesday, the White House released the written statement from Trump bearing the date July 26 — before quickly releasing an identical statement with the date removed. That led some of Trump’s critics to conclude that he had made the decision on Brennan’s security clearance weeks ago but that the White House strategically delayed an announcement for maximum political benefit.

“This might be a convenient way to distract attention, say from a damaging news story or two,” Sen. Mark R. Warner (D-Va.) said on Twitter. “But politicizing the way we guard our nation’s secrets just to punish the President’s critics is a dangerous precedent.”

Some Republicans, including Sen. Rand Paul (Ky.), applauded Trump’s move. In a statement, Paul sought to take credit for the idea of revoking Brennan’s clearance. “I urged the President to do this,” he said. “. . . his behavior in government and out of it demonstrate why he should not be allowed near classified information.”

Presidential historian Douglas Brinkley called Trump’s action unprecedented, saying he knew of no historical example of a president’s trying to “dehumanize and embarrass an outstanding intelligence officer like John Brennan.”

Brinkley suggested that the closest antecedent was President Richard Nixon’s attempts to use the Internal Revenue Service to harass people on his “enemies list” and Sen. Joseph McCarthy’s congressional hearings to try to identify and punish suspected communists inside the U.S. government in the 1950s.

“The public outcry of Brennan being stripped will echo long and far in the annals of American history,” Brinkley said. “It will be seen like McCarthyism — a dark stain on our democracy.”

Nearly 4.1 million Americans have federal government security clearances of varying levels up to “top secret,” according to government estimates. In some cases, ex-officials retain their clearances and are called on to provide advice or input on classified or highly sensitive matters, experts said. Some ex-officials also have jobs that require a security clearance.

It is not clear how much of an impact Trump will have if he seeks to strip others of their clearances. Comey and McCabe have said their security badges were automatically demagnetized after they were fired.

But the action was the latest in a long battle between Trump and top members of the intelligence and national security communities. During the 2016 campaign, a bipartisan group of national security experts, including Hayden, signed two “Never Trump” letters asserting that he “lacks self-control and acts impetuously,” has demonstrated “erratic behavior” and is “fundamentally dishonest.”

Since taking office, Trump has faced criticism that he has been reckless in his own handling of sensitive information, including disclosing highly classified material during an Oval Office meeting last year with the Russian foreign minister and ambassador to the United States. And at his Florida retreat, Mar-a-Lago, Trump appeared to discuss the U.S. response to a North Korean missile launch in full view of patrons.

Questions also have been raised about Trump’s staff, including son-in-law Jared Kushner, whose security clearance was downgraded in February before he was granted a permanent clearance in May. Former White House staff secretary Rob Porter was granted clearance despite allegations that he had been violent toward two ex-wives, which he has denied.

“This is not merely erratic, it’s somewhat dangerous, using clearances to get at political opponents,” Eliot Cohen, a former State Department counselor during the George W. Bush administration who organized one of the “Never Trump” letters, said of the president’s decision on Brennan.

Rep. Adam B. Schiff (Calif.), the top Democrat on the House Intelligence Committee, said on Twitter that Trump’s move demonstrates “how deeply insecure and vindictive he is — two character flaws dangerous in any President.”

“An enemies list is ugly, undemocratic and un-American. I also believe this action to silence a critic is unlawful,” Schiff said in a tweet.

Sen. Bob Corker (R-Tenn.), who, after tangling with Trump on foreign policy issues, is not seeking reelection called the president’s action a “banana republic kind of step.”

Sen. Susan Collins (R-Maine) said Brennan has been “far too political” in his commentary about Trump. But she added that recently retired intelligence officials generally have worthwhile expertise to offer and called Trump’s move “unwise.”